Whenever a bus comes, I'm always first on - always and there's a good reason for that... If there's two empty seats at the front nearside and I have my backpack, which is Mondays and Fridays (plus every other Saturday), then I'll take them. Firstly, because of my autism, I like to sit at the front nearside (nearside meaning the left) of the bus on the outside seat and secondly, I have reduced mobility what with getting older (I'm on the wrong side of 40) so going upstairs is not an option, nor is going to the back.
If someone younger than me is sitting where I want to park my a, then I'll ask them politely to move and generally they do comply, the same with anyone with a bag on the seat where I want to sit. You will get the odd w*r who doesn't and points out there are other seats but generally I don't get any problems. On days when I have my backpack with me and I think that someone might want to sit next to me, then I'll move it and it's the same if someone asks.
But to return to the point of this subject of queues, I may not like them and nearly always am the first on but, if there are people getting off the bus, then I'll stand slightly away from the front of the bus so's they can get off. Others may think I'm selfish for not joining a bus queue but that's their funeral - I'm not selfish because, if a bus pulls up and I see someone running for it, I'll hold it up for them...if I'm not getting it, that is.